What is the diameter difference between 215/55R17 and 235/55R17?

215/55R17 has an overall diameter of 26.31 inches (668 mm). 235/55R17 is 27.18 inches (690 mm). That's a 0.87 inch (22 mm) difference — 235/55R17 is taller.

Will 235/55R17 cause speedometer error on a car fitted with 215/55R17?

Swapping 215/55R17 for 235/55R17 produces a speedometer error of about 3.3%. Your speedometer will read lower than your actual speed — a 60 mph indicated reading is really 62 mph. Anything under 3% is usually acceptable without recalibration.

How many revolutions per mile does each size do?

215/55R17 turns 767 revs per mile. 235/55R17 turns 742 revs per mile. Taller tyres turn fewer times per mile, which lowers effective final-drive ratio.

What's the sidewall height difference?

215/55R17 has a sidewall of 118 mm (4.66 in). 235/55R17 sidewall is 129 mm (5.09 in). Lower-profile sidewalls give sharper steering response but less bump compliance.

Is 235/55R17 a safe plus-size upgrade from 215/55R17?

A plus-size upgrade is considered safe when overall diameter stays within ±3% — here the difference is 3.3%. This swap is outside the typical ±3% safe range and may require speedometer recalibration or affect ABS / traction control behaviour.

Tire size comparison

215/55R17 vs 235/55R17

Overall diameter, sidewall, revs per mile, and speedometer error — 235/55R17 is the taller tire, with a 3.3% speedo delta when swapping.

215/55R17

26.31in

668 mm overall diameter

235/55R17

27.18in

690 mm overall diameter

Diameter Δ

0.87 in

Speedo error

3.3%

215/55R17 revs/mi

767

235/55R17 revs/mi

742

Outside the typical ±3% safe plus-size band — you may want speedometer recalibration, and this change can affect ABS or traction control behaviour.

Full spec

Side by side

Metric	215/55R17	235/55R17
Section width	215 mm	235 mm
Aspect ratio	55	55
Wheel diameter	17″	17″
Sidewall height	118 mm	129 mm
Overall diameter	26.31 in (668 mm)	27.18 in (690 mm)
Circumference	82.66 in	85.38 in
Revolutions / mile	767	742

Other comparisons for these sizes

195/65R15 vs 215/55R17 205/60R16 vs 215/55R17 215/60R16 vs 215/55R17 225/60R16 vs 235/55R17 215/55R17 vs 215/50R17 215/55R17 vs 225/50R17 235/55R17 vs 235/50R18

FAQ

Frequently asked

What is the diameter difference between 215/55R17 and 235/55R17?: 215/55R17 has an overall diameter of 26.31 inches (668 mm). 235/55R17 is 27.18 inches (690 mm). That's a 0.87 inch (22 mm) difference — 235/55R17 is taller.
Will 235/55R17 cause speedometer error on a car fitted with 215/55R17?: Swapping 215/55R17 for 235/55R17 produces a speedometer error of about 3.3%. Your speedometer will read lower than your actual speed — a 60 mph indicated reading is really 62 mph. Anything under 3% is usually acceptable without recalibration.
How many revolutions per mile does each size do?: 215/55R17 turns 767 revs per mile. 235/55R17 turns 742 revs per mile. Taller tyres turn fewer times per mile, which lowers effective final-drive ratio.
What's the sidewall height difference?: 215/55R17 has a sidewall of 118 mm (4.66 in). 235/55R17 sidewall is 129 mm (5.09 in). Lower-profile sidewalls give sharper steering response but less bump compliance.
Is 235/55R17 a safe plus-size upgrade from 215/55R17?: A plus-size upgrade is considered safe when overall diameter stays within ±3% — here the difference is 3.3%. This swap is outside the typical ±3% safe range and may require speedometer recalibration or affect ABS / traction control behaviour.